Powerful low frequency sound waves are most often produced by electrodynamic loudspeakers using a large diaphragm to provide the required volume displacement and enough mass to resonate at low frequencies. The large diaphragm can be provided by loudspeakers in the audio device itself. The loudspeakers embedded in portable devices, e.g., laptops, tablets, and smart phones, are usually small. As a result, the loudspeakers' diaphragms are small as well and the resonance frequency is relatively high. A consequence is that the system's low cut-off frequency is mostly above 400 Hz. This high pass cut-off frequency results in the inaudibility of most low frequencies.
The same numbers are used throughout the disclosure and the figures to reference like components and features. Numbers in the 100 series refer to features originally found in FIG. 1; numbers in the 200 series refer to features originally found in FIG. 2; and so on.